OpenWrt as a device tracker

For Developers
1

Hi all,

I wanted to get some feedback on how I am using the OpenWrt RPC interface (luci-mod-rpc) to detect reliably, when a device is active or leaves the network.

I created a Python module called openwrt-luci-rpc to do this:

This module is consumed by the Home Assistant project, as per this PR.

Anyway, to get to my actual question:

Is the way I am detecting presence actually correct?

Here is the code I am using for OpenWRT v17 to determine if a device is reachable:

# Check if the Flags for each device contain
# NUD_REACHABLE and if not, skip.
if not int(device_entry['Flags'], 16) & 0x2:
    continue

That was working fine, but now since v18, using the ip neighbors ref rpc interface is used to get a list of connected devices, and there is no longer a Flags property.

There are other properties returned, such as the following:

        {
            "dev": "br-lan",
            "stale": true,
            "mac": "00:1E:EC:09:08:AD",
            "noarp": false,
            "dest": "192.168.7.5",
            "permanent": false,
            "failed": false,
            "family": 4,
            "proxy": false,
            "router": false,
            "reachable": false,
            "probe": false,
            "delay": false,
            "incomplete": false
        },

I tried using the reachable and stale booleans, to indicate presence, but they flap a lot, even when they have not left the house (this flapping is probably only true for non-wired devices, like phones).

Anyway, I don't fully understand what each of these properties actually mean, and I would appreciate any advice on how to intelligently use them to determine if a smart phone has left the building (for example).

Right now, my logic for v18+ is, if the device entry exists at all in the ip neighbors list, then consider it at "home" and not "away".

This seems to work pretty well, and I see my phone drops off the list after about 10-15 minutes (iPhone).

Anyway, any thoughts on this would be appreciated!

CC @jow who I know has contributed to the luci-mod-rpc package.

2

I think you should fetch wireless client statuses from:

ubus call hostapd.wlan0 get_clients
3

Thanks @vgaetera. I should note that my module must work with non wireless OpenWrt routers. E.g. only routers acting as the DHCP server. There are other better solutions to mine, which are geared for wireless as you said.